A Ti-Zr-Cu-Ni-Co-Fe-Al-Sn amorphous filler metal for improving the strength of Ti-6Al-4V alloy brazing joint

Ti50Zr27Cu8Ni4Co3Fe2Al3Sn3 (at%) amorphous filler metal with low Cu and Ni contents in a melt-spun ribbon form was developed for improving mechanical properties of Ti-6Al-4V alloy brazing joint through decreasing brittle intermetallics in the braze zone. Investigation on the crystallization behavior of the multicomponent Ti-Zr-Cu-Ni-Co-Fe-Al-Sn amorphous alloy indicates the high stability of the supercooled liquid against crystallization that favors the formation of amorphous structure. The Ti-6Al-4V joint brazed with this Ti-based amorphous filler metal with low total content of Cu and Ni at 1203 K for 900 s mainly consists of α-Ti, β-Ti, minor Ti-Zr-rich phase and only a small amount of Ti3Cu intermetallics, leading to the high shear strength of the joint of about 460 MPa. Multicomponent composition design of amorphous alloys is an effective way of tailoring filler metals for improving the joint strength.